Pedernales Falls State Park Prothonotary Warbler Nest Box Study: Blue Grosbeaks & Buntings

Prothonotary Warbler Occurrence In Texas

Central Texas draws the western line for the Prothonotary Warbler range. This species occupies much of eastern North America up to the southern boarder of Ontario Canada.
Prothonotarys' nest in natural cavities but also readily use nest boxes located on or near water. Flooded swamps represent ideal habitat but they will also nest along rivers or small bodies of water.
In May 2007 I saw a brightly colored male Prothonotary Warbler at Pedernales Falls State Park bird blind. After some research I learned male birds have been seen building nests in neighboring counties to Blanco County. Further research revealed a pair of Prothonotary Warblers successfully nested at Heard Wildlife Sanctuary in McKinney, Texas.
In December 2007 I decided to undertake a nest box study at the park. January through February 2008 I hiked the entire Pedernales River and tributaries within park boundaries, in an effort to choose the best sites. Habitat selection proved a challenge do to high flood levels along the river.
Five sights were eventually selected where two nest boxes each were placed. Most boxes were attached to trees however two were attached to metal poles. These boxes were monitored from March through June 2008 on a weekly basis. A Breeding Bird Study was conducted at each nestbox location in 2008 and will be continued in 2009.

Saturday, June 14, 2008

Blue Grosbeaks & Buntings

Blue Grosbeaks, Painted Buntings and Indigo Buntings were the most common songsters in the park today as summer brought nearly 100 degree temperatures. Today I found male Blue Grosbeaks singing at three sites. The Twin Falls & Pedernales River Blue Grosbeak nest still has the female sitting on two eggs. The song of this species is similar to the Painted Bunting but hoarser. Rufous-crowned Sparrows continue to be heard along Wolf Mountain Trail and one was recorded on the bluff at Twin Falls this morning.

Walking into Tobacco Creek I passed the Acadian Flycatcher nest #1. It appears the single nestling fledged. I heard the male singing in the draw. At Tobacco Creek Seep I discovered a second active Acadian Flycatcher nest. This nest is located on the same pecan tree limb overhanging the seep that the Black-chinned Hummmingbird nest was on. The hummingbird nest was predated on by a squirrel over a month ago. I watched the female Acadian Flycatcher fly into a leafy area so after my survey I investigated and found the female on the nest. Acadian Flycatcher nests appear to be located on the lower canopy of mature trees, thus quite visible, although they are the same size as the abundant ball mosses.

The seep at Tobacco Creek continues to bring fresh water dripping off old logs, (photo to the left). Today Red-eyed Vireo, Carolina Chickadees, the Acadian Flycatcher and Painted Buntings frequented this seep. The photo above is one of the easier climbs down to the Pedernales River at Tobacco Creek.